On Thu, 22 Dec 2011 15:16:59 +0100 Michael Büsch <m...@bues.ch> wrote:
> On Thu, 22 Dec 2011 07:40:19 -0600 > Jeff Epler <jep...@unpythonic.net> wrote: > > > I understand the rest, but what's the + 0.1 part doing? > > The +0.1 is to protect against floating point inaccuracies. > Imagine the ceil() operation yields a 200.0, for example. But > due to floating point inaccuracies it's actually represented > as 199.9999999999999. So the (implicit) int cast would (tail)-cast > it to 199, instead of the correct 200. The +0.1 avoids that. > > > fwiw the code was added to fix this bug: > > http://sourceforge.net/tracker/?func=detail&aid=2478266&group_id=6744&atid=106744 > > > > I think that ceil, round or (implicit in integer division) floor are all > > OK as fixes to the original problem, so I'd be tempted to just drop the > > useless ceil() call instead and leave the behavior unchanged. > > Ok, well. I'm don't really understand the code good enough to have an > opinion on this, but changing the code to this: > > servo_mult = traj_period_nsec / nsec; > > should maintain the current semantics, but avoid the floating point stuff. > > Please also note that some older compilers are confused by that floating > point stuff there and throw internal errors. (That's how I got attracted > to that code). So it should be fixed either way. Should I resend the patch, or are you going to apply that manually? -- Greetings, Michael. ------------------------------------------------------------------------------ Write once. Port to many. Get the SDK and tools to simplify cross-platform app development. Create new or port existing apps to sell to consumers worldwide. Explore the Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join http://p.sf.net/sfu/intel-appdev _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
